The following discussion is not an admission that anything described below is common general knowledge.
U.S. Pat. No. 6,340,527 to Van Soest et al. describes microparticles having a particle size of 50 nm to 1 mm consisting of a chemically cross-linked starch shell containing an active ingredient. The particles are obtained by first preparing an oil in water emulsion of the active ingredient in a hydrophobic phase and starch, or a dispersion of a solid active ingredient and starch in water. The active ingredient may be a medicament which is released in the digestive tract when the starch degrades.
U.S. Patent Application Publication U.S. 2008/0241257 to Popescu et al. describes a nanoparticle of a biodegradable polymer containing a hydrophilic cationic drug such as streptomycin. The biodegradable polymer may be chitosan. A pharmaceutical preparation containing the nanoparticles is administered to a patient orally and the nanoparticles release the drug in vivo. The drug can be complexed with a naturally occurring polymer, such as dextran sulfate. The drug, optionally complexed, is mixed with the biodegradable polymer followed by an inorganic polyanion to form the nanoparticle. In one example, the nanoparticles were about 560 nm in average size, had a zeta potential of about +54 mV and were used to treat tuberculosis in mice.
U.S. Pat. No. 7,550,441 to Farokhzad et al. describes a conjugate that includes a nucleic acid ligand bound to a controlled release polymer system contained within a pharmaceutical compound. Some examples of the polymer system are based on poly(lactic) acid (PLA) and have mean particle sizes ranging from 137 to 2805 nm. The ligands have an affinity for a target and are prepared through the Systemic Evolution of Ligands by Exponential Enrichment (SELEX) process.
U.S. Patent Publication 2009/0312402 to Contag et al. describes nanoparticles with encapsulated nucleic acid. The polymer may be PLA, PLG or PLGA and PEG. The particles may have ligands or antibodies attached to them for targeting the nanoparticles to a site of interest. The nanoparticles may have a polymer coating to provide controlled release. The particles are in the size range of about 50 nm to about 500 nm, with most of them in the sub-200 nm range.
U.S. Patent Publication 2011/0244048 to Amiji et al. describes a method of making a nanoparticle comprising combining an aqueous solution of a solubilized therapeutic agent with a water-soluble polymer comprising polyethylene glycol (PEG) and a fatty acid. These components self assemble into a nanoparticle. Various dextran based particles have means sizes ranging from 14 nm to 430 nm. The therapeutic agent may be doxorubicin.
U.S. Pat. No. 8,048,453 to Sung et al. describes nanoparticles of chitosan, poly-glutamic acid, and an active agent. The particles have a mean particle size between about 50 nm and 400 nm. The active agent may be insulin for the treatment of diabetes or an active for treating Alzheimer's disease. The nanoparticles may be freeze-dried and loaded into a capsule for oral administration.